Rational design of cyclopropane-based chiral PHOX ligands for intermolecular asymmetric Heck reaction
作者:Marina Rubina、William M Sherrill、Alexey Yu Barkov、Michael Rubin
DOI:10.3762/bjoc.10.158
日期:——
rigid cyclopropyl backbone was synthesized and tested in the intermolecularasymmetricHeck reaction. Mechanistic modelling and crystallographic studies were used to predict the optimal ligand structure and helped to design a very efficient and highly selective catalytic system. Employment of the optimized ligands in the asymmetricarylation of cyclic olefins allowed for achieving high enantioselectivities
synthesized. The Pd-complexes of these ligands show high catalytic activity and enantioselectivity in catalyzing the asymmetricHeckreaction. A dramatic switch in enantioselectivity is realized usingligands with and without substituents at the benzylic position of the ligand. Ligands 1 with H as the substituents offer products in (R)-configuration while ligands 2 with the methyl as substituents result
Synthesis, Application and Kinetic Studies of Chiral Phosphite-Oxazoline Palladium Complexes as Active and Selective Catalysts in Intermolecular Heck Reactions
作者:Zahra Mazloomi、Marc Magre、Efrem Del Valle、Miquel A. Pericàs、Oscar Pàmies、Piet W. N. M. van Leeuwen、Montserrat Diéguez
DOI:10.1002/adsc.201701603
日期:2018.4.17
This study identifies new phosphite‐oxazoline ligands that have been successfully applied in the palladium‐catalyzed intermolecular asymmetric Heck reaction. The design of the new phosphite‐oxazoline ligands derives from a previous successful generation of phosphine‐oxazoline ligands, by replacing the phosphine group with several π‐acceptor biaryl phosphite moieties. With these simple modifications
chiral diphosphine-oxazoline ferrocenyl ligands were synthesized and used efficiently in the palladium-catalyzed asymmetric intermolecular Heck reaction of 2,3-dihydrofuran with aryl triflate and cyclohexenyltriflate. The tuning of the regioselectivity was realized by means of different palladium precursors and by changing the electronic factor of the ligands. A plausible rationale based on the existed
Palladium-catalyzed asymmetric arylation of 2,3-dihydrofuran: 1,8-Bis(dimethylamino)naphthalene as an efficient base
作者:Fumiyuki Ozawa、Akihiko Kubo、Tamio Hayashi
DOI:10.1016/s0040-4039(00)91654-x
日期:1992.3
Reaction of 2,3-dihydrofuran with aryl triflate (1) in the presence of a base and a palladium catalyst, generated in situ from Pd(OAc)2 and (R)-BINAP, gave (R)-2-aryl-2,3-dihydrofuran (2) and a small amount of (S)-2-aryl-2,5-dihydrofuran (3). The enantiomeric purity of major product 2 was strongly affected by the base. 1,8-Bis(dimethylamino)naphthalene (proton sponge) as a highlybasic and sterically